John h



(No Model.)

J. H. PURDY.

LAMP.

No. 498,341. Patented Mar. 14, 1893.

UNITED STATES PATENT OFFICE.

JOHN H. PURDY, OF CHICAGO, ILLINOIS.

LAMP.

SPECIFICATION forming part of Letters Patent No. 493,341, dated March14, 1893. Application filed September 12, 1892. $erial No. 445,672. (Nomodel.)

To all whom it may concern:

Be it known that I, JOHN H. PURDY, of Chicago, in the county of Cook andState of Illinois, have invented certain new and useful Improvements inLamps, of which the following is a full, clear, and exact description,reference being had to the accompanying drawings, forming a part of thisspecification, in which Figure'l. is a side view of a lamp embodying thefeatures of my invention,the base being shown in section, and Fig. 2. isa central vertical sectional view of the lamp and base, said lamp beingshown in the position ordinarily occupied when in use.

Corresponding letters of reference in the different figures indicatelike parts.

My invention relates to spherical lamps more especially adapted forjewelers use, and consists of an improvement upon Letters-Patent No.232,206, issued to me on the 14th day of September, 1880. In saidLetters-Patent I have described and shown a lamp, the body of which isspherical in form and arranged to rest loosely in a cup-shaped base,theobject of this construction being to tilt the lamp to any desired angle;but, as there is nothing in said construction to serve as acounter-poise for the Wick-tube, great difficulty has been heretoforeexperienced in keeping the same in position when placed at a givenangle. Roughened leather, rubber, sand, pumicestone and other thingshave been placed in the cup-shaped base to form a friction-surface, butwith only partial success. The jar upon the work table upon which thelamp is placed caused by pounding or otherwise, sooner or later causesthe lamp tube to fall to a horizontal position in spite of the utmostprecaution, thereby changing the uniform character of the flame andenabling the alcohol to be wasted.

"The object of my invention is to overcome this objection; and to soconstruct the body of a spherical lamp that it may retain its positionat whatever angle the wick tube may be tilted;-all of which ishereinafter more particularly described and claimed.

Referring to the drawings, A represents the body of the lamp which isspherical in form and is adapted to rest loosely in the cup shaped baseB. The wick tube 0 is made of metal in the usual manner.. The body A ispreferably formed from glass or other vitreous material, and is so blownor molded that that portion D diametrically opposite the wicktube isthicker than elsewhere. I prefer to gradually reduce the thickness ofsaid body from the part which forms the bottom when the tube is upright.I have shown said reduction as terminating at the top of the lamp; butit is obvious that it may be at any intermediate point. As shown, thecurve of the interior is made eccentricto the outer circumference. Ihave found in actual practice,that the lamp as thus constructed, may betilted in any desired position and will retain said positionindefinitely without being affected by jar or other movement.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. The combination in a lamp of a cup shaped base, a spherical lamp bodyloosely mounted therein, and a wick tube, the walls of said lamp bodybeing made thicker at the bottom or opposite the wick tube,substantially as shown and described.

2. A spherical lamp body, the surface of the interior of which iseccentric to that of the exterior,in combination with a wick tube andcup shaped base, substantially as shown and described.

In testimony whereof I have signed this specification, in the presenceof two subscribing witnesses, this 1st day of December, 1891.

JOHN H. PURDY.

WVitnesses:

D. H. FLETCHER, J. B. HALPENNY.

